Patent GB-1343424-A (GB)
Title: Photographic-type-composing
IPC: B41B21/28
Filed: 1970-03-20
Abstract: 1343424 Photographic type-composing INTERNATIONAL PHOTON CORP 4 May 1971 [20 March 1970] 13752/70 Heading B6W Flashes of mochromatic collimated and planepolarized light from sources 2, 4, Fig. 1, emerging as beams 3, 5 are deflected by deflectors 6, 8 to emerge along one of a plurality of light paths 50, 52 to pass through a selected character of a matrix array 10, and after passing through a merging system comprising a reflecting face 12 and a semi-reflecting face 14 emerge along one of the paths 54. The beam is then deflected by a coarse deflector 16 and a fine deflector 144 to emerge in a selected position at 56. The character images now enter a line segment positioning mechanism, whereby they are directed to one of four segment locations 68, 70, 72, 74 and on to the photosensitive surface. The deflector 6 (or 8) comprises electro-optic crystals 110, 112, 114, 116, 118, Fig. 3, and birefringent crystals 100, 102, 104, 106, 108, the ordinary and extraordinary rays from the crystals 100, 102 being widely separated by mirrors 120, 121, 122 and 123-128 or by prisms, the matrix being shown at 140. The matrix array comprises a strip 140, Fig. 5, carrying in one row and transparent on an opaque background an alphabet of characters in upper and lower case, while other rows for symbols may be located on other levels as at 143. The rows are separated by blank zones 145 into two sections aligned with deflectors 6, 8. A plurality of strips can be mounted on a frame 182, movable vertically for font selection. Alternatively, the characters may be mounted on a movable strip on drum surface and the light source illuminated at selected instants when a desired character is in a pirojection zone, or a mirror carriage moves along a stationary strip. The coarse deflector 18 comprises electro-optic crystals and birefringent crystals 148-159, Fig. 2, by which the right-hand character a can be deflected between 161 and 162 and the left-hand character 5 between 165, 166, but only the shaded zone 138 is utilized, so that the selected image passes to the fine deflector 144. The various discrete positions which the light entering the deflector 144 can occupy are spaced 16 typographical units apart, and light in any of these positions can be deflected to 16 positions 1 unit apart by the deflector 144, producing a composed line-segment 146. The images at 146 each pass to an electro-optical crystal 40 and a birefringent crystal 42 and are deflected or not in a vertical direction, normal to the plane of Fig. 1, to reach a mirror 32 or 34, and by means of further crystals 48, 46 and mirrors 36, 38, arrive at a lens system 64 in a selected one of the zones 68, 70, 72, 74. Alternatively, the light emerging at 56, Figs. 1 and 6, passes to a selected one of mirrors 22, 24, 26, 28, which is displaced virtically into the light path. The lens system controls magnification for point size, and comprises a plurality of lenses mounted on a rotatable turret. Each lens may be formed as a narrow strip if the characters selected on the matrix are all on one horizontal line. Where there are gaps between the segment zones 68, 70, 72, 74, as when using mirrors as shown in Fig. 6, these gaps are eliminated by using a separate magnifying lens for each zone. In order to bring the left end of lines of different point size to a common datum line on the photo-sensitive surface, it is necessary to shift the location of the first character before magnification, which is done by adding a correction value to the accumulated width total which controls the deflectors 16, 144. Similarly, lines can be centred.